This invention relates to an apparatus and method for applying an overlay, such as an overlay of veneer, to a curved surface, such as the curved surface which typifies the outer surface of a molding strip and like elements.
Applying overlays to a workpiece is useful and desirable in a number of applications. For instance, such might be applied to a metal element to impart to the element the appearance of wood and where metal is selected for the composition of the element because of fire resistance or other desirable properties. As another example, a veneer overlay might be applied to a workpiece where the workpiece is composed of an inferior grade. or species of wood, or perhaps a particle board type of material, to impart to the finished product a better appearance. This is a particularly important use of veneer overlays at the present time where the world supply of quality wood is diminishing.
An element, such as a piece of molding strip, a door jamb, trim material, etc. very frequently will be provided with an exterior surface which is substantially straight extending in a direction paralleling the longitudinal axis of the strip, but which in transverse cross section extends in a curving expanse, with this curving expanse delineating valleys and ridges joined by irregularly curved surface regions. Because of the complex curvature involved, there are problems connected with applying an overlay to such a surface, with the overlay during the application process tending to be stretched and cracked when making it properly conform to the substrate that it is to cover. Additionally, proper bonding of the overlay to the workpiece or substrate is a problem by reason of inadequate pressure being applied to the overlay in all regions that the overlay is to contact the substrate. Another problem that a manufacturer encounters is that the contours of different workpieces will vary, and a press designed to accommodate one style of contouring is not easily changed to make it suitable for applying overlays to another style of contouring.
A general object of this invention is to provide an improved press for applying an overlay to a workpiece or substrate which is operable to conform the overlay to the curvature of the substrate surface in a manner minimizing stretching, breaking, cracking, etc.
Another object is to provide such a press which is relatively flexible in operation, in the sense that it is relatively easily adjusted to accommodate different contours in the exterior surfaces of a substrate.
A further object is to provide an overlay applying press which features what are referred to herein as multiple depressers, each individually and selectively movable to produce at their extremities and when actuated, pressure in localized regions of an overlay against the substrate to which it is applied.
Yet a further object of the invention is to provide a novel method for applying an overlay to the outer surface of a workpiece, wherein lineal pressure regions of limited lateral extent are produced with such pressure regions paralleling the longitudinal axis of the workpiece, the pressure regions being successively established in a manner dictated by the particular contour being surfaced.